Spring actuated core retainer



Nov. 5, 1968 T. R. KRETSCHMER ETAL 3,409,094

SPRING ACTUATED CORE RETAINER 2 Sheets-Sheet 1 Filed May 31, 1967 INHEODCRJARE R. K

VENTORS RETSCHMER ELVI N C. HIRONAKA JOSEPH H. GOLANT A r TOR/V5 Y 1968T. R. KRETSCHMER ETAL 3,409,094

SPRING ACTUATED CORE RETAINER 2 Sheets-Sheet 2 Filed May 31, 1967 Fig.3

United States Patent 3,409,094 SPRING ACTUATED CORE RETAINER Theodore R.Kretschmer, Port Hueneme, and Melvin C.

Hironaka, Camarillo, Calif., assignors to the United States of Americaas represented by the Secretary of the Navy Filed May 31, 1967, Ser. No.643,325 7 Claims. (Cl. 175-242) ABSTRACT OF THE DISCLOSURE The inventionis a spring actuated core retainer comprising a tubular body which is tobe attached to the lower end of a core sampling barrel. Within the bodyare two rotatable closure elements connected to two torsion springswhich tend to bias the closure elements so as to close the core barrelafter a sample has been taken. Holding means restrain the closureelements during descent and penetration of the core barrel; upon removalof the barrell, pressure from the ocean sediment pivots the holdingmeans from engagement with the closure means allowing the torsionsprings to bias the closure elements to a closed position.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

Background of the invention Field of the invention.This inventionrelates to a closure device and more particularly to a spring actuatedcore retainer to be used in combination with a core barrel for thepurpose of retaining core samples taken from the ocean bottom.

Description of the prior art.The problem of retaining a core sampletaken from the ocean bottom has long been known by oceanographers andhas sparked various devices as solutions to the problem. One of theearly devices consisted of flexible metal fingers mounted on a ringwhich fitted into the interior of a core barrel near the cutting shoe.These flexible metal fingers allowed the core sample to enter but werebiased so that the sample was prevented from movement out of the barrel.The primary disadvantage of this type of device was that it restrictedthe core barrel entrance during corer penetration and it seriouslydisturbed and remodeled the core sample as the sample entered the corebarrel.

Another device consisting of a pair of jaws mounted on a frame whichslides up and down the exterior of the core barrel has been developed;this device is held externally on the core barrel by a hook at alongitudinal position approximately equal to the expected core barrelpenetration. Ideally the jaws will be resting upon the surface when thecore barrel has finished its penetration and as the core barrel isretrieved the jaws close over the end of the barrel when the barrelreaches the sediment surface. However, the disadvantages with thisapparatus are that the depth of penetration of the core barrel cannot bepredicted closely enough to allow proper positioning of the jaws, nor dothe jaws completely and effectively prevent a core sample loss sinceimmediately upon pulling a suction is exerted on the core sample tendingto pull the sample out of the core barrel. The result is that in manycases the core sample has been lost by the time the core barrel has beencompletely removed from the sediment.

A third type of core retainer which is of recent design is bestillustrated by a patent to J. E. Sanders et al., Patent No. 3,285,354,which illustrates a retainer consisting of two curved gates which arelinked to a longitudinally 3,409,094 Patented Nov. 5, 1968 slidingexternal sleeve. The sleeve is in an upward position upon penetration ofthe core barrel, thus holding the gates open, and the sleeve is forcedinto a lower position upon removal of the barrel, thus causing the gatesto close. Such a device is a definite improvement over the first twodevices mentioned; however, it too has disadvantages in that it willonly operate in certain types of ocean sediment such as firmly packedsand, but such a device would not work in looser types of sediment whichwould not be able to establish the required forces upon the slidingsleeve to cause closure. In addition, the requirements of a slidingsleeve and corresponding linkages leading to the gates necessitate anoverly large di ameter core barrel which, in turn, establishes a poorarea ratio (the area ratio is the ratio of the difference between thesectional core barrel area and the sectional core sample area to thesectional core sample area).

Summary of the invention Our invention solves the abovementionedproblems by providing a device which will work in all types ofunderwater sediment and which has a very good area ratio. The advantagesare achieved by providing a spring actuated core retainer comprising incombination a tubular body, a hinge connected to the tubular body, aclosure means rotatably attached to the hinge for opening and closingthe interior of the tubular body, spring means connected to the tubularbody and to the closure means for biasing said closure means into aclosed position, and a retention means connected to the tubular body andthe closure means for selectively holding the retainer means in an openposition, and responsive to downward sediment pressure for releasing theclosure means, whereby the closure means in held open by the retentionmeans during penetration of the device into the ocean bottom and theclosure means is biased closed during pullup of the device from theocean bottom.

An object of the invention is to provide a spring actuated core retainerwhich is operable in all types of ocean bottom sediments and especiallyin soft cohesive materials.

Another object of the invention is to provide a spring actuated coreretainer which has a low area ratio thus causing the least disturbanceto a soil sample.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings wherein:

Brief description of the drawings FIG. 1 is a partial sectional view ofa preferred embodiment of our invention showing the device in an openposition to receive a core sample;

FIG. 2 is a full sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a partial sectional view of the FIG. 1 embodiment illustratingthe device in a closed position; and

FIG. 4 is a full sectional view taken along line 44 of FIG. 3.

Description of the preferred embodiment Referring now to the drawingswherein like reference numerals designate like or corresponding partsthroughout the several views there is shown in FIG. 1 a sectional viewof our apparatus in an open position. The apparatus comprises a tubularbody 10 having an upper portion 12 and a lower portion 14 and having anexterior portion or surface 16 and interior portion 18. The tubular bodymay be connected at its upper portion 12 to a core barrel 20 by anysuitable means such as a bayonet connection (not shown). The interior ofthe core barrel 20 may be a core sample liner 22 which may be used toprotect and house a core sample so as to expedite handling and storageof a core sample once it is brought back to a surface vessel. A cuttingshoe 24 may be connected to the lower portion 14 of the tubular bodybyany suitable means such as by being threaded thereon as designated at26.

-T he tubular body may have oppositely disposed longitudinal grooves 28and 30 out within its interior portion 18 and transversely oppositelydisposed apertures 32 and 34 drilled through the body, the grooves andapertures for receiving the mechanisms necessary to achieve theadvantages of our invention.

The remaining elements of our invention which are mostly housed in theinterior 18 of the tubular body 10 are comprised of a closure means, ahinge, a spring means, and a retention means.

The closure means may comprise two oppositely disposed arcuate elements36 and 38 shown in open position in FIGS. 1 and 2 and in a closedposition in FIGS. 3 and 4. The arcuate elements 36 and 38 areconstructed so that when in an open position they are substantiallyflush with the core liner 22 and the inner diameter 40 of the cuttingshoe 24 so as to present a substantially constant sectional area to acore sample as it is cut from the ocean bottom; the constant sectionalarea is best seen in FIG. 2. To achieve the substantially flushinterior, the interior portion 18 may be counterbored. In addition, thearcuate elements are so designed that the elements 36 and 38substantially close the interior 18 of the tubular body and formgenerally two equal halves of a hollow right circular cone, as shown inFIGS. 3 and 4.

Each of the arcuate elements 36 and 38 is rotatably attached tooppositely disposed hinges which may be comprised of a support ring 42,tabs 44 and 46, pins 48 and 50, and arms 52 and 54. The support ring 42may be located within the interior 18 of the tubular body and positionedin a fixed location by any suitable means such as by being boltedthrough hole 62 to the tubular body 10. A lower end 64 of the supportring 42 is spaced from the cutting shoe 24 by a circular spacer ring 66which rests upon a circular transverse face 68 of the cutting shoe 24.Tabs 44 and 46 may be attached to the support ring 42 by welding and aredesigned to be rotatably attached, in turn, to the arms 52 and 54,respectively, which may be accomplished by pins 48 and 50, respectively,inserted into corresponding holes in the tabs and arms. The arms, inturn, are rigidly connected to the arcuate elements 36 and 38,respectively, thus allowing the arcuate elements to be rotated from anopen to a closed position. The support ring 42 may have oppositelydisposed slots 70 and 72 designed to allow the arms 52 and 54 to berotated.

Spring means such as torsion springs 74 and 76 are connected to thearcuate elements 36 and 38, respectively, and to the tubular body 10. InFIG. 1 the torsion springs 74 and 76 are shown in a biased positiontending to move the arcuate elements together while in FIG. 3 thetorsion springs 74 and 76 are shown in position after they have closedthe arcuate elements. The arms have apertures at and 77 to receive theends of the torsion springs so as to keep the springs in position. It isto be noted that the tabs 44 and 46, the arms 52 and 54 and the torsionsprings 74 and 76 are located in the two longitudinal grooves 28 and 30,respectively, which is a factor in enabling the arcuate elements 36 and38 to achieve their substantially flush position.

The retention means are connected to the'tubular body 10 and to thearcuate elements 36 and 38 and are for the purpose of holding thearcuate elements in an open posi-' tion during the descent andpenetration of the core barrel into the ocean bottom and are responsiveto downward sediment pressure for releasing the arcuate elements onceremoval of the device is started. The retention means may be comprisedof catch elements 78 and 80 and holding elements 81 and 83. The catchelements 78 and 80 are each rigidly attached such as by welding toarcuate elements 36 and. 38,. resuept v lv an m y. be. .L-shap d s ownin the figures. The holding elements, in turn, comprise hook portions 82and 84 for engaging respectively the catch elements 78 and 80, and atrigger portion upon which the sediment forces act. f The triggerportion. of the holdingelements, in turn, comprise mounting elements-86and 88 and planar slanted surfaces 90 and 92 whichare slanted so thatthey extend generally upwardly away from the tubular body 10. Thegenerally V-shaped notch'formed-by each slanted surface and the exteriorsurface of thetubular body tends to wedge sediment against the surfacesand thereby cause activation when the device begins itsupward movementduring removal. Each'of the holding elements comprised of the hookelement, the mounting element, and the slanted surface may be madeintegral as is illustrated in our preferred embodiment. I e

Mounting blocks 94 and 96-may be oppositely disposed such as by weldingor bolting upon the exterior surface 16 of the tubular body and containpivot pins 98 and 100, respectively,-about which the holding elementsare pivotally mounted by way of their mounting elements 86 and 88,respectively. The arrangement just described allows the hook portions 82and 84 to project into the apertures 32 and 34, respectively, of thetubular body so as to engage the respective catch elements 78 and 80which may also project into the respective apertures 32 and 34.

Operation The operation of our invention is relatively simple and quitereliable, two necessities that are required when apparatus is tofunction automatically in a hostile environment. The entire coringdevice is either lowered or dropped froma vessel and proceeds to descendto the ocean bottom. Usually because of its weight or by some drivingmechanism the core barrel is driven into the bottom sediment to sliceaway a core sample.

The function-of the cutting shoe 24 is to do the slicing and direct asample into the 'interior of the core barrel. In our invention the coresample will pass first into the interior of the cutting shoe then intothe interior 18 of the tubular body 10 before entering the interior ofthe liner 22. As is noted in FIG. 2, a constant cross section presentsitself tothe core sample so as to prevent any disturbance or damage tothe sample.

During this penetration stage the exterior surface 16 of the tubularbody 10 will experience a frictional drag of the sediment'as the devicecontinues to penetrate. This friction will cause an upward force uponthe pivotable holding element. Since the arcuate elements 36 and 38 wereplaced in an open position on board the vessel, there will be notendency during penetration to cause closure as the hook portions andcatch elements will remain engaged.

However, upon the removal of the coring device from the ocean sedimentthe surfaces 90 and 92 will experience sediment forces -opposin'g'theirupward movement. These forces will be sufiicient to activate the device,the forces being created by the wedging of the sediment against thesurfaces or by the pressure exerted against any fiat surfaced body as itmoves through a fluid medium. The forces acting upon the surfaces and,therefore, upon the holding elements cause them to rotate about theirrespective pivot pins 98 and 100thereby pivoting the hook portions 82and 84 from engagement with their respective catch elements 78 and 80.Removing the restraint from the biased torsion springs 74 and 76 allowsthem to force the arcuate elements 36 and 38 into a closed position asshown in FIGS; 3 and 4. V

I The advant'ages'in our invention are that the arcuate elements 36 and38 close immediately upon lifting of the coring device. This will occureven before removal of the device from the sediment. Thus, the suctionforces inherent in any pulloutfr'om the ocean bottom cannot act upon thecore sample to remove it from the core barrel. In addition, theplacement of a spring means within the system causes the arcuateelements to close immediately upon release thus supplying its own forceof closing and not requiring the forces to come from outside the coringdevice as was done in the prior art. Furthermore, the holding elementsmay be so constructed as to operate very easily so that the slightest offorces acting upon the triggering portions pivot the holding elementsout of engagement with the catch elements. This allows operation of ourdevice in extremely soft sediment such as soft, oozy mud or clay and yetour device is still able to operate in the harder types of materialwithout loss of efliciency. The broader applications available with ourdevice makes it an extremely desirable tool since, in many cases, thetype of sediment found at the ocean bottom is not known prior toreceiving a sample.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

We claim:

1. A spring actuated core retainer comprising in combination:

a tubular body having a lower, an upper, an exterior,

and an interior portion; a hinge connected to said tubular body; aclosure means rotatably attached to said hinge for opening and closingthe interior of said tubular body;

spring means connected to the tubular body and to the closure means forbiasing said closure means into a closed position; and

a retention means connected to the tubular body and the closure meansfor selectively holding the closure means in an open position andresponsive to downward sediment pressure for releasing the closuremeans,

whereby said closure means is open during penetration of the oceanbottom and biased closed during pull-up from the ocean bottom. 2. Aspring actuated core retainer as claimed in claim 1 wherein:

the spring means is a torsion spring. 3. A spring actuated core retaineras claimed in claim 1 wherein:

the closure means comprises two oppositely disposed arcuate elementswhich form when in a closed position two halves of a generally rightcircular cone;

each arcuate element being rotatably attached to oppositely disposedhinges;

said tubular body having transversely oppositely disposed apertures; and

said retention means comprising two catch elements each catch elementrigidly attached to each of said arcuate elements, and holding elementseach pivotally mounted upon the exterior portion of the tubular body,extending through the tubular body apertures for engaging the respectivecatch elements when the interior portion of the tubular body is open. 4.A spring actuated core retainer as claimed in claim 3 wherein:

the pivotable holding element comprises a hook portion for engaging thecatch element and a trigger portion upon which sediment forces act tocause pivoting, the trigger portion disposed generally exterior of thetubular body. 5. A spring actuated core retainer as claimed in claim 4wherein:

the trigger portion of the holding element comprises a mounting elementand a planar slanted surface, said surface extending generally upwardlyaway from said tubular body. 6. A spring actuated core retainer asclaimed in claim 5 including:

mounting blocks oppositely disposed upon the exterior of the tubularbody; and said mounting element of said trigger portion pivotallyattached, one mounting element to each of said mounting blocks. 7. Aspring actuated core retainer as claimed in claim 6 including:

a support ring mounted to the interior portion of the tubular body forsupporting the hinge; a core barrel connected to the upper portion ofthe tubular body for receiving a core sample; a cutting shoe connectedto the lower portion of the tubular body for cutting a core sample; anda spacer ring located between the cutting shoe and the support ring forspacing the cutting shoe and the support ring.

References Cited UNITED STATES PATENTS Re. 18,500 6/1932 Stone -254 X1,987,853 1/1935 Howard 175-251 2,022,100 11/1935 Wright 175-2542,028,579 1/1936 Wright 175-254 2,215,710 9/1940 Miller 175-242 X2,471,616 5/ 1949 Goodwin 175-254 3,285,354 11/1966 Sanders 175-242 NILEC. BYERS, 111., Primary Examiner.

